the neoadjuvant therapy Patients with HER2+/HR+ (HER2+ and ER+ and/or PR+) tumor will receive single agent T-DM1 for 12 weeks (3,6 mg/kg q3w) with or without standard endocrine therapy (tamoxifen in premenopausal women and an aromatase inhibitor in postmenopausal women, if not contraindications are present, in a standard daily dosage). The control group will receive trastuzumab in 3-weekly schedule (8 mg/kg as loading dose and then 6 mg/kg q3w) in combination with the same standard endocrine therapy, if no contraindications are existent.